Method and apparatus for producing tobacco smoke filters



March 5, 1963 R. F. DYER Ei AL 3,079,663

METHOD AND APPARATUS FOR PRODUCING TOBACCO SMOKE FILTERS Filed May 21,1958 2Sheets-Sheet 1 {D m k E i u l: -w -8 0 a E l E si k 2 5 w Q s g l0 F 3E SUPPLY TOW Riclu zrdE .Dger Paul Gallagher INVENTORS moteumMETHOD AND APPARATUS FOR PRODUCING TOBACCO SMOKE FILTERS 2 Sheets-Sheet2 R. F. DYER ETAL March 5, 1963 Filed May 21, 1958 RichardRDger PaulGallagher INVENTORS' BY APTORNm and cigar holders.

ilnited rates hatent 3,079,663 Miififill) ANB APPARATUS FGR PRQDUCINGTGRAQCO SMGKE PETERS Richard F. Dyer and Paul Gallagher, Kingsport,Tenn,

assignors to Eastman Kodak Company, Rochester, N31,

a corporation of New Jersey Filed May 21, 1958, Ser. No. 735,900 11Claims. (Cl. 28-4) This invention relates to the production of tobaccosmoke filters suitable for cigarettes, pipes, and cigarette Inparticular this invention is concerned with an apparatus and process fortreating a continuous filament crimped tow to substantially increase thefiltration efiiciency thereof for the removal of nicotine, tars andaerosol particles from the tobacco smoke while at the same timeelfecting a reduction in weight of filter material required andmaterially improving the processing of the tow into filter plugs.

In the industry at the present time a large number of tobacco smokefilters are made from continuous crimped filament tow. Such tow materialis very useful for making such filter element constructions for a numberof reasons. The continuous filament tow works well in automatic filtermaking machinery. The filaments due to their longitudinal arrangementcontain elongated aligned parallel type passageways for the smoke.However, while in making filters from such tow although it has beendesired to preserve to some extent the longitudinal align- -ent, it hasalso been desired to alter the crimp arrangement in a manner that thecn'mps are out of registry, thereby producing shoulders in the filterupon which the smoke may impinge. lso the putting of the crimps out ofregistry enables the obtaining of a firmer filter with lower quantitiesof material.

In the art prior to the instant invention, various means have been usedto try and alter the filament parallelism and to randomize the locationof the knees of the crimp to some extent. Such means have includedmechanical vibrators or strikers, pinch rolls and the like. However,such procedures as inducing a high static electrical charge on the towby means of rubber rollers or the alternate application of high and thenlow tension by passing the tow from slow speed to high speed and then tolow speed rolls or the beating of the tow by mechanical heaters havecertain disadvantages. The generation of a high charge of staticelectricity on the tow may present a hazard if any volatil matter ispresent or if at a later step in the process it is desired to treat thetow with certain liquids or powdered additives. The application of hightensions or the beating of the tow with vibrators not only weakens thetow and may cause breaks therein but such prior art type of treatmenthas destroyed to a substantial extent the effectiveness of the crimp. Inother words, in the prior art one must choose between a good crimp thatremains in the treated tow or a deficiency of crimp that is randomizedand, therefore, in each instance the most efiicient and economicalfilter plug is not obtained.

Another and perhaps more serious problem encountered in the prior arttype of operation is that it has not been possible to utilize tow havinga particularly high degree of crimp. That is, highly crimped tow mayhave certain weak points at the point of crimp. Consequently, when ithas been attempted to process highly cn'mped "ice tow in accordance withprior art procedures with rolls or vibrators, such attempts have notbeen too satisfactory because of the breaking of the highly crimped tow.Furthermore, as already briefiy mentioned, the prior art processes ofbeating and tensioning the tow in an elfort to break up the registry ofthe knees of the crimp often causes the filaments to be strained beyondthe yield point. Thus the sharp angular crimp originally in thefilaments is often removed because the stresses of blooming the tow aregreat enough to permanently remove a substantial amount of the crimp.

It is, theerfore, believed apparent that the developent of a simplermore efiective method for treating continuous filament crimped tow foruse in the manufacture of tobacco smoke filters whereby the tow may beopened up, the crimps placed out of registry and yet the crimp notremoved from the tow as well as filament breakage avoided represents ahighly desirable result. After extended investigation we have found animproved apparatus and method whereby prior art difiiculties as abovediscussed may be eliminated or materially reduced.

One object of this invention is to provide an apparatus and means forprocessing a continuous filament crimped tow into a filter plug having arandomized filament arrangement, said filaments retaining a high .degreeof their original crimp so that a filter may be obtained which has aneificiency that is relatively high to the weight of the filter material.Another object is to obtain a well opened up tow suitable for filterswithout substantially impairing the strength or the degree of crimp inthe individual filaments. A particular object is to provide a simple andefiective apparatus arrangement for converting a dense continuousfilament crimped tow into a well opened up filter tow readilysusceptible to treatment with plasticizer and the like. Still anotherobject is to make a filter from continuous filament crimped tow, whichfilter for a specific filament size and resistance to air flow, is moreefiicient in removing tars and nicotine than prior art filament filters.A still further object is to utilize tows which have a higher crimp thanheretofore tolerated with the prior art processes used in making filtersfrom such tow. Other objects will appear hereinafter.

For a more complete understanding of our invention reference will bemade to the attached drawings forming a part of the present application.

In these drawings FIG. 1 is a schematic flow diagram of the processingof the continuous filament tow into a filter plug for tobacco smokefilters.

FIG. 2 is a schematic diagram of the overall apparatus arrangement ofapparatus which would be used in carrying out the process of the presentinvention.

FIG. 3 is a detailed cross-sectional view of the finding jet of thepresent invention.

FIG. 4 is a part semi-diagrammatic front end view of the jet shown inH6. 3.

Referring now to FIG. 1, as indicated above the general overallarrangement for making filters in accordance with the present inventionis shown. As mentioned above, one object of the tow conditioning offilter tow is to convert the densely packed crimped tow from the supplypackage into a relatively fiufiy resilient flat sheet of filaments whichare in a randomized state, then to establish an adhesive condition onthe filaments by suitto 50 p.s.i. gauge. .high velocity gas how isproduced which is evenly disjet and the rolls 6. the exit zone of thejet the filaments can thus be violentbly 7 described above.

be seen that where opening and banding and fiutfing were formerlyseparate steps, these steps are combined in our newprocess. Thepreferred system now involves feeding the towat a constant rate to ablooming jet, taking up the bloomed tow at an equal or reduced speedrelative to the feed rate and then subjecting it to the action of asecond blooming jet, then to the adhesive spray, and finally removing itfrom the tow conditioning zone at a reduced rate relative to the rate ofthe initial tow feed. For example, tow feed No. 1 may be at the rate of50 y.p.m., tow feed No. 2 at the rate of 49 y.p.m. and tow .feedNo 3 atthe rate of 48 y.p.m. Thus duringeach blooming process the tow isuiiderconditions which promote its relaxation v 7 I v In FIG. 2. theoverall'apparatus arrangement is shown in more detail. (Srimped andcompacted tow 1 is with drawn from bale 2 over guides 3 and 3a by thefirst pair of tow feed rolls 4. The tow then passes through blooming jet5 which is supplied with-gas at a pressure of The design of the jet issuch that a tributed over the width of the rectangular-shaped jet. Theaction of this high velocity gas separates the individual filaments fromeach other and spreads the tow out into'a band or sheet of filaments. Atthe same time the ifilamen-ts are given a strong thrust by the air flowsuch that tension is generated in the tow between the rolls 4and the jet5. The tow then passes to roll pair 6 which is driven 'atsnch a speedrelative to roll pair 4 as to allow the tow to'be in arelaxed statebetween-the In this area and particularly in 1y agitated and vibratedsuch that each filament is separated from the other and the crimp kneesassume completely random position relative to each other.

This cycle of blooming or debundlizing is then repeated with roll pairs6 and 9 and jet 7. Here tension is again present between rolls 6 and jet7 due to the in- :tiuence of the high velocity jet air on the tow. Rollpair 9 however is driven at a speed relative to roll pair 4S so thatbetweenjet 7 and rolls 9 therevis substantially no tension other thanthat required to prevent excessive sag in the tow. Also in the slacktension zone between -je't 7 and rolls 9 there is located .spray booth 8which applies plasticizer or other material to the tow. Since the tow isrelaxed and the filaments wellseparated at this point excellentdistribution and even application of the plasticizer or the like on eachfilament is possible.

After leaving roll pair 9 the tow passes to the garniture of thecigarette making imachine'sh'own overall at 10. To insure good controlover the process a common drive motorll drivesall the individual rollsand the cigarette machine 10 by chain, cog belt or other positive drivemeans. Interposed between the motor 11 and roll pairs '4 and 6 there arevariable speed transmissions 12 and 13 such that the relative speeds ofroll ;pairs 4, 6 and9' can be adjusted to establish the desired degreeof relaxation in each blooming stage.

In some cases it may be desired to eliminate one blooming stageand inthis case, roll pair 4 and blooming jet 5 may be omitted with the towpassing directly from guide 3a to roll pair 6. This arrangement may notbloom the 'tow as etiectivelyas the two-jet assem- However, the one jetassembly of the present invention will process the tow better than priorart procedures. Thereare other'alternatives. One

is to retain maximum crimp in the bloomed tow which may leave a fewgroups of unopened filaments in the tow. The other is to use somewhathigher air pressure than is required with two jets. well but may removesome slight amount of crimp from the opened filaments.

Another alternative is to utilize one flufiing jet 7 and do some tensionblooming between rolls 4 and 6 with or without the aid of a beaterbetween the two sets of rolls. This method requires a larger tow toprovide a specified filter efiiciency and firmness.

These several alternatives illustrate the flexibility of the new method.The arrangement shown in FIG. 2 will give'the most efiicient filter,will require the lowest total denier, and will make the fir'mest rodusing fine filaments.- However, other considerations, such as the typeof filter making equipment the manufacturer already has on hand, maymakeit desirable to utilize one of the above alternatives and these areincluded in the venturi bodyparts when assembled to the end plates 18and 18a coact-to form elongated slot venturi entrance 22, a venturithroat 23 and a diverging venturi exit 24.-

The-two nozzle plates 16 and 17 are assembled to venturi body platesHand 14 respectively by cap screws as indicated at 25 and 26. Thesenozzle plates coact with each other to form a slot-like yarn entrancepassage 27 which convengesat 28. The nozzle plate 16 also co acts withventuri plate 15 to form a wedge-shaped chamber .29 which is incommunication with the circular air chamber 20 via'slot passage 21. Atthe down stream side of this chamber 29 it converges at an angle ofabout fifteen degrees so that air passing through is accelerated to ahigh velocity at the transition between the venturi entrance 22and theventuri throat 23. Nozzle plate 17 and venturi plate 14 coact in asimilar manner. As apparent from FIG. 3 that although only slot 22,airchamber 20, etc. have been referred to specifically, that on theotherside of part17 there are comparable slots, chambers and the like.Hence, further description thereof appearsto be unnecessary.

The tow enters the jet through passageway 27 and atthe tipof the nozzle2 8, it is subjected to the impingement-ofthe high velocity sheets ofair emerging from the venturi entrances. It maybe observed frominspection of these'ctional v'iew shown in FIGURE 3 of the drawings thatthere is a low-included angle of incidence. Also the tow is subjected tothe impingement "of two'thin intersecting fiat sheets of air emergingfrom "the passages tormed by the mating plates 15, 16 and 14, 17 so thatthere are two high velocity sheets of air In the throat 23 air and emering from the entrances. tow are intermixed and parallelized in theirdirection of flow and the velocityeflect of the air generates a tensionin' the tow'and a suction in'the nozzle entrance 27. This suction isstrong enough to make the jet self 'threading, i;e. it will suck the towinto the jet. As the high velocity gas and tow mixture leaves theventuri throat 23 and enters the diverging throat 24, the air begins tolose velocity and expand. This action has the effect of exploding thetow and causing the filaments of the 'tow to diverge also, thusseparating the filaments one from another. 'Also the filaments tend tovibrate muchin the manner of ribbons attached to the front of anelectric fan. This :action further assists This will bloom the towpressure spot.

-tions have been found to be desirable. divergence of the venturi shouldbe from four to ten seven times the length.

ao'zaeea in separating the filaments. Recalling that between the jet andthe downstream feed roll the tow is allowed to relax and Contact, thefilaments also move longitudinally relative to each other so that kneesof crimp in adjaccnt filaments are thrown out of phase in a completelyrandom manner. Thus as the tow emerges from the jet the filaments arecompletely rearranged relative to each other as compared with theirrelative positions on entering the area of high velocity gas flow.

So far we have considered only the cross section of the jet. We will nowconsider FIG. '4. The principal purpose of FIG. 4 is to illustrate thatthe jet shown in FIG. 3 is not the usual round or cylindrical type ofjet known in the prior art but is an elongated slot type of jet. In FIG.4 the jet has been shown broken away on one corner to show the airchamber. The width of the jet may be, for example, 4-20 inches.

Referring in more detail to FIG. 4, it will be observed that the airinlet pipe is shown at 20 as are the nozzle plate parts 16 and 17. Theopening indicated at 27 is the entrance passageway for the tow being fedto the jet. PEG. 4 also shows parts 18 and 13:: which are the endplates. An end plate is merely a metal plate bolted onto the side of theparts discussed in the description of FIG. 3 to provide an end closurefor the jet. Also, the construction of the end plate is such that thespacing of the parts may be accomplished to the desired degree.

if we look in the transverse plane i.e., along the width of the jet, itwill be seen that an even sheet of air flow is generated in the venturithroat from side to side of the jet. This is because air very quicklywill equalize variations in pressure or velocity in a given zone orenclosure. Thus if high pressure was present in the middle of the jet itwould quickly level out by transfer of air from the high pressure spotto the adjacent low Furthermore, the jet is so proportioned that thesupply of air in circular chamber 20, and in the converging chamber 29is large relative to the amount that can pass into and through theventuri.

.tinual leveling of air velocities and pressures tend to expand the towwidth not only in the jet entrance but also in the venturi throat 23 andexit 24.

To obtain the most efficient use of air compatible with the mosteiiective blooming of the tow certain propor- The angle of degrees witheight degrees being preferred. The length i the diverging portion 24should be about four to ten times the length of the throat 23 andpreferably about The nozzle throat length 23 should be about three timesits width. The total area of the entrance slots as 22 should be about.10 times the area of the venturi throat. This latter ratio, however, isadjustable depending on the amount of suction or back pressure desiredin the entrance nozzle 2. A low ratio tends to increase the suctionwhile too high a ratio causes back pressure or blow back in the nozzleentrance 27. The width of the jet is largely determined by the width towhich it is desired to spread the tow. The proportion of the area of theventuri throat to the denier of the tow is not unduly critical butvalues in the order of one square inch per 50,000 denier are esirable.The included angle of the venturi throat entrance formed by plates 14and 15 is preferably 90 but may vary from 4-5 to 135.

The manner in which the tow enters and leaves the jet can be arranged toimprove the blooming. In general a straight line pass is less desirable.Bringing the tow in parallel to the jet axis and removing it at about aright angle produces improved results. Also about a right angle bend inthe tow as it enters the jet and 21 second approximate right angle bendas it leaves with the tow either reversing its general direction of flowor ending up proceeding in the same direction are also bene- EXAMPLE IFilter rods were made by the air blooming process of this inventionusing a 54,000 denier tow containing approximately 20,300 filament-shaving an average size of 2.6 denier. For comparison, filter rods weremade by the prior art proce lures using a 72,000 denier tow containingapproximately 27,700 filaments having an average size of 2.6 denier. Thephysical characteristics and filtering eiiiciency of both rods are shownin the following table.

Present Prior artinvent-iontension air bloomed, bloomed, Total Denier54, 000 72, 000

Denier per Filament. 2.6 2. 6 Crlrnps per Inch 18 16 Weight of mm, Rod,gm 74 8 Pressure Drop 90 mm. Rod, inches 1 l 11.2 11.3 Hardness of Rod5. 7 7.8 Pressure Drop 15 mm. Tip, inches H2O. 2. 1 2. 1 Ta: Removed,percent 34 30 Tests of pressure drop, hardness, removal and weight wereconducted under standard conditions using procedures and apparatus whichare accepted in the cigarette industry. The hardness value is a measureof rod deformation under a specified load and a low number indicatesgreater firmness. It will be seen that the air blooming process requiresless material, makes a firmer rod, and results in more effectivefiltration.

EXAMPLE II Filter rods were made by the air blooming process of thepresent invention using 5 d./f.70,000 denier tow. Filter rods were madeby the prior art tensioning process using 5 d./f.-70,000 denier tow andalso 5 d./f.- 80,000 denier tow. The comparative tests are tabulatedbelow.

Air Tension Tension bloomed, bloomed, bloomed, Total Denier 70, 000 70,000 80, 000

Denier per Filament 5 5 5 Crimps per Inch 7. 5 7. 5 8.0 Weight of 90 mm.Rod, gm" .37 .80 92 Pressure Drop of 90 mm. Rod, inches 1. 16 9 1. 2 TarRemoval, percent" 20 12 17 The improvement obtained by the air bloomingprocess of the present invention is again clearly evident. The presentinvention gives improved crimp retention and a more inter-twinedcondition of the tow.

In Table A which follows there is summarized the results of tests madeon a range of denier/filament sizes tow size-s, comparing filter plugsmade by the jetblooming process of the present invention and filterplugs made by prior art processes. In general it will be noted thatwhere rod weights are equal the percent tar removal or the jet bloomedyarn of the present invention is higher; or if the percent tar removaland pressure drops are equal then the weight of the jet bloomed filterplug is less.

p rases Table A I Air Jet Control Tow Plug Crimps Weight Hard- PressurePercent rod made Example No. D./f. denier code per inch of 20 rods nessdrop tar reby tenmoval No. No. 7 slon pressure pressure blooming III 2.054, 000 403 X7 14. 5 6. 3 11.9 33

'2. 0 54, 000 IAXP 17 13. 3 8. 1 8. 6 24 Yes. 7 2.0 72,000 lAXM 17 17. 58. 9 13. 3 Yes.

IV 2. 5 54, 000 40E 17 14. 9 5. 7 ll. 2

2. 5 54, 000 lAWX 17 13. 1 11.7 7.0 Yes. 2. 5 72, 000 lAW'l 17 16. 4 7.811.0 Yes. V 3.0 70, 000 40K 11 16. 9 5. 8 10. 8

3. 0 84, 600 lAXU ll 19. 4 6.8 11.3 Yes. VI 5. 0 000 40J 7. 5 17. 4 6. 76. 5

5.0 80, 000 lBAE .8. 0 l8. 5 5. 5 6. 9 Yes.

In making these plugs of Table A the filter plug making ,apparatus ofFIG. 2'was operated typically in a manner as will be described in theexample which follows:

EXAMPLE VII In this example the followilig pressures,

speeds and the like conditions were used.

Tow denier 57,000 Denier/filament 3 Crimps/Inch 18 Speed of roll set 4'.:m v 54.4 pressure to jet 5 p.s.i. gauge Speed of roll set 6 y.p'.m54.5 Air pressure to jet 7 p.s.i. gauge;. 25 Speed of roll set 9 y.p.m..53.4

"The tow was under no tension between jet 5 and roll "set 6 and betweenjet 7 and roll set 9. The speed of the roll sets 4 and -6 in this casewere equal with the .jet 5 being used to flex-the tow much in the mannerof a spring, but this flexing-opened up the tow, randomized the filamentarrangement and the locations of the crimp x-knees.

traction oi the tow was-allowed to take place. Since crimped tow ishighly elastic it is possible to have two Between roll set 6 and 9, anactual slight con pairs of rolls at equal speeds but still have the towrelaxed slightly between the jet and the output rolls since this slackor relaxed condition represents recovery of the stretching done betweenthe input rolls and the jet input due to tension generated by the jetair flow.

While the exactmechanism by which the air jets of the present inventionbloom the tow is not fully known,

pressures within the range of 5 to 100 p.-s.-i.g. may be used. The rollspeeds of the various rolls may be as follows: Input teed roll set '4,200 y.p.-m.; rolls 4 to 6 speed ratio, 1.20/1 to .7/ 1; rolls 6 to9speed'ratio, 1.20/1 to .8/ 1.0. The total denier (T.D.) of the tow mayvary bet-ween 15,000 to 100,000 and the denier per filament (D.F.')' maybe .1 to 8. As pointed out above, this invention works well on highlycrimped filaments. Hence, the crimp in the tow would generally not beless than 7 crimps' per inch, and may be l7 or 18 per inch. In cer---tain filaments the crimp may be higher, say up to per inch. Whereas,in spray booth 8 for cellulose ester filaments weus'ed the plasticizerglycerol triacetate to the extent of 812% on the filaments, otherplasticizers as dimethoxycthyl phthalate'or triethyl citrate may beused. Or other materials such as dextrin or gum arabic inaqueouss'olution may be applied.

and is the. measured roll surface speed. The term psi. gauge meanspounds per square inch above atmospheric pressure as measured by anystandard pressure recording instrument.

Although the examples given relate particulary to cellulose acetatefiber, other textile fiber tows may also ;be successfully bloomed by themethod of this invention. Such materials as cellulose acetatebutyrate'cellulose acetate propionate, cellulose triacetate, acrylamidepolymers and copolymers', polyolefins'and polyester-fibers could also beused although the method of producing an ad- -he'sive state in the towmay be varied to use other plasticizers, adhesives,-solvents or the likewhich are'com patible with the particular filaments being treated.

The invention has been described in detail with particular reference topreferred embodiments thereof, but 7 from said package through the nipof a pair of feed rolls,

passing the tow from the rolls through a blooming jet having arectangular 'divergentexit section whereby the individual filaments ofthe tow are violently agitated, vi-

brated, and separated by the expansion of the air in the rectangulardivergent exit section-of a blooming jet so:

that the tow is opened up and the crimp put out of registry; said airflow being distinctly in the direction of movement of the tow therebyadvancing the tow, withdrawing the tow from the jet by further rolls ata speed such that'thetow is not put under tension, passing thiswithdrawn tow through a further jet where the tow is subjected tofurther air treatment,'then passing the'proc- 'essed tow through a spraybooth and further rolls, said last-mentioned rolls also operating at aspeed so that the tow is not put under tension and conducting theprocessed tow from the last-mentioned rolls to filter formation; andthroughout the process avoiding tensions in the tow greater than thoserequired to support and transport the tow.

2. A process in accordance with claim 1 wherein the speed of feed to thefirst jetis between 30250 y.p.m.

3. The process in accordance with claim 1 wherein a the tow enters'thejets at an angle and exits at an angle.

4. The process in accordance with claim l wherein the tow fed throughthe process is made up of continuous cellulose acetate filaments of .1-8denier per filament and 15,000100,000 total denier crimped to at least17 crimps per inch.

5. A process in accordance with claim 1 wherein'the tow fed to theprocess is 2-5 inches wide and in the process is spread out to at least10 inches in width.

6. In a process 'for the manufacture of tobacco smoke filter elementsfrom continuous'crimped compacted tow the improvement step whichcomprises opening up the tow and putting the crimp out of registry by asubstantially tensionless process comprising the passage of .the

tow .through a high velocity slot venturi jet having a rectangulardivergent exit section supplied with air including contacting thecompact ribbon-like crimped tow with two intersecting fiat thin streamsof high velocity air at a low angle of incidence, passing both the towand air stream through a venturi throat to further accelerate the airvelocity, then causing the air to expand and lose velocity in thedivergent exit portion of the venturi such that the compact crimped towis caused to expand and bloom in width and thickness and the filamentsare longitudinally displaced relative to each other whereby the crimp isput out of registry without breaking the filaments.

7. In a method of manufacturing tobacco smoke filters from crimped towin a package form, the steps which comprise withdrawing said tow fromsaid package through the nip of a pair of feed rolls, passing the towfrom said rolls through a high velocity rectangular cross sectionventuri jet supplied with a gas, said jet being positioned in closeproximity to said rolls and the jet being of a construction whereby thegas flows from the jet in two sheets of gas in a direction relativelyparallel to the direction of movement of the tow so that the tow isadvanced by the gas, and conducting said tow after it passes throughsuch slot jet to further steps for forming a filter therefrom andthroughout the process avoiding tensions in the tow greater than thoserequired to support and transport the tow.

8. An apparatus arrangement for carrying out processes for advancing andopening tow in the manufacture of filters which comprises three pairs offeed rolls in series, said feed rolls being adapted to receive and passthrough the nip of the rolls a continuous filament crimped tow, a highvelocity rectangular cross section venturi jet positioned between thefirst and second roll pair, said jet when supplied with gas beingadapted to advance and open said tow, a further jet and spray boothpositioned between the second and third roll pair, and means for formingin series with the third roll pair for forming tow processed in saidjets into filter elements.

9. In an apparatus for opening tow in the manufacture of filters twopairs of rolls in series, said rolls being adapted to receive and passthrough the nip of the rolls a crimped tow, a high velocity rectangularcross section venturi jet having a divergent exit section adapted to besupplied with a gas positioned between the two pairs of rolls and inclose proximity to the first pair of rolls, said jet being of aconstruction having an inlet for tow as it is received from the firstpair of rolls and an exit from the jet, the internal construction of thejet being such that the gas supplied to the jet is caused to contact thetow and then is accelerated in the same direction as the movement of thetow to a high velocity, and is then caused to expand as it is dischargedfrom the jet in the divergent exit section so as to exert both alongitudinal and divergent transverse thrusting force on the individualcrimped filament of the tow.

10. An apparatus construction in accordance with claim 9 wherein thehigh velocity rectangular cross section venturi jet is positioned aboveand at an angle to the path of the .tow between the two pairs of rolls.

11. An apparatus in accordance with claim 9 wherein the high velocityrectangular cross section venturi jet is 4-20 inches wide.

References ited in the file of this patent UNITED STATES PATENTS2,435,891 Lodge Feb. 10, 1948 2,476,582 Browne et a1 July 19, 19492,657,433 Merrirnan Nov. 3, 1953 2,737,688 Jackson Mar. 13, 19562,750,653 White June 19, 1956 2,774,680 Hackney et al Dec. 18, 19562,783,609 Breen Mar. 5, 1957 2,793,418 Pfau May 28, 1957 2,794,239Crawford et a1 June 4, 1957 2,794,480 Crawford et a1 June 4, 19572,805,671 Hackney et al Sept. 10, 1957 2,807,862 Griset Oct. 1, 19572,812,569 Lawson et al Nov. 12, 1957 2,815,761 Shearer Dec. 10, 19572,828,752 Jackson Apr. 1, 1958 2,908,045 Stevens Oct. 13, 1959 2,914,835Slayter et al Dec. 1, 1959 2,966,198 Wylde Dec. 27, 1960

8. AN APPARATUS ARRANGEMENT FOR CARRYING OUT PROCESSES FOR ADVANCING AND OPENING TOW IN THE MANUFACTURE OF FILTERS, WHICH COMPRISES THREE PAIRS OF FEED ROLLS IN SERIES, SAID FEED ROLLS BEING ADAPTED TO RECEIVE AND PASS THROUGH THE NIP OF THE ROLLS A CONTINUOUS FILAMENT CRIMPED TOW, A HIGH VELOCITY RECTANGULAR CROSS SECTION VENTURI JET POSITIONED BETWEEN THE FIRST AND SECOND ROLL PAIR, SAID JET WHEN SUPPLIED WITH GAS BEING ADAPTED TO ADVANCE AND OPEN SAID TOW, A FURTHER JET AND SPRAY BOOTH POSITIONED BETWEEN THE SECOND AND THIRD ROLL PAIR, AND MEANS FOR FORMING IN SERIES WITH THE THIRD ROLL PAIR FOR FORMING TOW PROCESSED IN SAID JETS INTO FILTER ELEMENTS. 